yes it is

although it could be something else

please let us know your RAM config (interleaving & size & connector color for each module)

& once again

You should start diagnostic with minimal RAM config.

OS 9.1 will work with 1x 32mb module and no VM with extensions disabled

and no pci of course; you could even unplug any device such as zip or cd rom

and remove your pram battery as it's too old